Application of a coating on a medical device

ABSTRACT

Methods and devices for the provision of a coating on an implantable medical device. The coating includes a bio-absorbable carrier component. In addition to the bio-absorbable carrier component, a therapeutic agent component can also be provided. The methods and devices provide a coating having improved uniformity and coverage which in turn allow for greater control of the amount and dosage of the coating.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/238,554, filed on Sep. 28, 2005, which claims priority to, and thebenefit of, U.S. Provisional Application No. 60/613,745, filed Sep. 28,2004, for all subject matter common to all applications. The disclosuresof said applications are hereby incorporated herein by reference intheir entirety.

FIELD OF THE INVENTION

The present invention relates to devices and techniques for applyingcoatings to medical devices. More specifically, to devices andtechniques for applying coatings to medical devices, such as stents,balloons, and catheters. The coatings can be used for delivery of one ormore biologically active agents, providing controlled short or long termrelease of biologically active components from the surface of themedical device.

BACKGROUND OF THE INVENTION

Therapeutic agents may be delivered to a targeted location in a humanutilizing a number of different methods. For example, agents may bedelivered nasally, transdermally, intravenously, orally, or via otherconventional methods. Delivery may vary by release rate (e.g., quickrelease, slow release, or biphasic release). Delivery may also vary asto how the drug is administered. Specifically, a drug may beadministered locally to a targeted area, or administered systemically.

With systemic administration, the therapeutic agent is administered inone of a number of different ways including orally, inhallationally, orintravenously to be systemically processed by the patient. However,there are drawbacks to systemic delivery of a therapeutic agent, one ofwhich is that high concentrations of the therapeutic agent travels toall portions of the patient's body and can have undesired effects atareas not targeted for treatment by the therapeutic agent. Furthermore,large doses of the therapeutic agent only amplify the undesired effectsat non-target areas. As a result, the amount of therapeutic agent thatresults in application to a specific targeted location in a patient mayhave to be reduced when administered systemically to reducecomplications from toxicity resulting from a higher dosage of thetherapeutic agent.

An alternative to the systemic administration of a therapeutic agent isthe use of a targeted local therapeutic agent delivery approach. Withlocal delivery of a therapeutic agent, the therapeutic agent isadministered using a medical device or apparatus, directly by hand, orsprayed on the tissue, at a selected targeted tissue location of thepatient that requires treatment. The therapeutic agent emits, or isotherwise delivered, from the medical device apparatus, and/or carrier,and is applied to the targeted tissue location. The local delivery of atherapeutic agent enables a more concentrated and higher quantity oftherapeutic agent to be delivered directly at the targeted tissuelocation, minimizing or eliminating broader systemic side effects. Withlocal delivery, the therapeutic agent that escapes the targeted tissuelocation dilutes as it travels to the remainder of the patient's body,substantially reducing or eliminating systemic effects.

Local delivery is often carried out using a medical device as thedelivery vehicle. One example of a medical device that is used as adelivery vehicle is a stent. Boston Scientific Corporation sells theTaxus® stent, which contains a polymeric coating for deliveringPaclitaxel. Johnson & Johnson, Inc. sells the Cypher® stent whichincludes a polymeric coating for delivery of Sirolimus.

Targeted local therapeutic agent delivery using a medical device can befurther broken into two categories, namely, short term and long term.The short term delivery of a therapeutic agent occurs generally within amatter of seconds or minutes to a few days or weeks. The long termdelivery of a therapeutic agent occurs generally within several weeks toa number of months. Typically, to achieve the long term delivery of atherapeutic agent, the therapeutic agent must be combined with adelivery agent, or otherwise formed with a physical impediment as a partof the medical device, to slow the release of the therapeutic agent.

What is desired is a coated medical device wherein the coating isapplied in a manner that provides a uniform consistent coating. Thecoating can be a bio-absorbable delivery agent having non-inflammatorycharacteristics that is able to be prepared in combination with at leastone therapeutic agent for the delivery of that therapeutic agent to bodytissue in a controlled release manner.

In applying coatings to medical devices, such as stents and catheters,coverage and uniformity are important factors in the getting optimalperformance out of the coated medical device. If a device does not haveproper coverage then there may be areas on the device that do not haveproper coating which can lead to all the problems typically associatedwith uncoated devices. Similar problems can arise when the coating isnot uniform. Non-uniform coatings can cause inconsistent interactions,especially when a therapeutic agent is being delivered. Ideally, thecoating should be uniform over the medical device so that dosage andinteraction with tissue can be better controlled.

SUMMARY OF THE INVENTION

There is a need for an application technique for applying uniformconsistent coating to an implantable medical device for therapeuticpurposes. In accordance with the present invention a method and devicefor applying a coating to a medical device, such as a stent, balloon, orcatheter, are provided that can produce uniform consistent coverage in arepeatable and controllable manner.

In accordance with a first aspect, an applicator is provided forapplying a coating to a medical device, the applicator features a sheathhaving a first end, a second end, and a lumen between the first end andthe second end, the first end being flared and having a cross-sectionalarea greater than a cross-sectional area of at least a portion of thelumen and wherein the sheath is sized and dimensioned to fit over themedical device providing a clearance between the sheath and the medicaldevice for receiving a coating substance for application of the coatingsubstance to the medical device.

In accordance with another aspect, a method is provided for preparing acoated medical device. The method involves providing a medical deviceonto which a coating is to be applied, providing a coating substance forapplication onto the medical device; and applying the coating substanceto the medical device using an applicator featuring a sheath having afirst end, a second end, and a lumen between the first end and thesecond end, the first end being flared and having a cross-sectional areagreater than a cross-sectional area of at least a portion of the lumenand wherein the sheath is sized and dimensioned to fit over the medicaldevice providing a clearance between the sheath and the medical devicefor receiving a coating substance for application of the coatingsubstance to the medical device.

In accordance with certain aspects, applying the coating substance tothe medical device includes placing the applicator onto the medicaldevice; and filling the applicator with the coating substance. Incertain embodiments this may also include removing the applicator fromthe medical device leaving a residual coating of the coating substanceon the medical device. In some embodiments, the applicator is placedonto and removed from the medical device by sliding the applicator on oroff the medical device.

In accordance with other aspects, applying a coating substance to themedical device includes placing the coating substance on the medicaldevice and spreading the coating substance over the medical device bysliding the applicator over the medical device.

In accordance with certain aspects of the present invention, the methodfurther includes curing the coating substance on the medical device toform the coating. Curing with respect to the present invention generallyrefers to thickening, hardening, or drying of a material brought aboutby heat, UV, reactive gas, or chemical means.

In accordance with some aspects, the method further includes the step ofplacing a protective sleeve over the medical device to protect thecoating on the medical device.

In accordance with other aspects, the medical device is a stent,balloon, or catheter. In some embodiments a stent is located on an endof a catheter for deployment by the catheter.

In accordance with one aspect, a cap is provided for use in theapplication of a coating to a catheter. The cap features a section oftubing configured to fit on the end of the catheter to seal the lumen atthe end of the catheter during the application of a coating. In someembodiments the cap is a cap stylet. The cap stylet features a styletconfigured to fill a lumen of the catheter and a section of tubingattached to the stylet sized and dimensioned to be fitted on the end ofthe catheter to seal the lumen of the catheter.

In accordance with another aspect, a method of applying a coating to acatheter is provided. The method includes providing a catheter having aproximal end, a distal end, and a lumen between the proximal and distalends, providing a coating substance or application onto the catheter,providing a cap configured to fit onto an end of the catheter, placingthe cap onto an end of the catheter, and applying the coating substanceonto the catheter, wherein, the cap prevents coating substance frompenetrating the lumen at the end of the catheter. The coating substancecan be applied using an applicator.

In accordance with one aspect, a system is provided for use in preparinga coated catheter, the system includes a cap stylet including a styletconfigured to fill a lumen of the catheter and a section of tubingattached to the stylet sized and dimensioned to be fitted on an end ofthe catheter to seal the lumen of the catheter; and an applicatorfeaturing a sheath having a first end, a second end, and a lumen betweenthe first end and the second end, the first end being flared and havinga cross-sectional area greater than a cross-sectional area of at least aportion of the lumen and wherein the sheath is sized and dimensioned tofit over the medical device providing a clearance between the sheath andthe medical device for receiving a coating substance for application tothe medical device. In certain embodiments the system may furtherinclude a protective sleeve configured to be place over the catheter toprotect a coating on the catheter.

In accordance with another aspect, a method of coating a catheter isprovided. The method includes providing a catheter having a proximalend, a distal end, and a lumen between the proximal and distal ends;providing a coating substance or application onto the catheter;providing a cap stylet configured to fit onto an end of the catheter;providing an applicator featuring a sheath having a first end, a secondend, and a lumen between the first end and the second end, the first endbeing flared and having a cross-sectional area greater than across-sectional area of at least a portion of the lumen and wherein thesheath is sized and dimensioned to fit over the medical device providinga clearance between the sheath and the medical device for receiving acoating substance for application of the coating substance to themedical device configured to apply a coating to the catheter; placingthe cap stylet onto an end of the catheter; and applying the coatingsubstance onto the catheter using the applicator; wherein the cap styletprevents coating substance from penetrating the lumen at the end of thecatheter.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned features and advantages, and other features andaspects of the present invention, will become better understood withregard to the following description and accompanying drawings, wherein:

FIG. 1 is a diagrammatic illustration of a medical device, according toone embodiment of the present invention;

FIG. 2 is a cross-sectional view of the medical device in accordancewith one aspect of the present invention;

FIG. 3 is a cross-sectional view of the medical device in accordancewith another aspect of the present invention;

FIG. 4 is a flow chart illustrating a method of making a coated medicaldevice, in accordance with one embodiment of the present invention;

FIG. 5 is a flow chart illustrating a variation of the method of FIG. 4using an applicator in accordance with one embodiment of the presentinvention;

FIG. 6A is a diagrammatic illustration of an applicator in accordancewith one embodiment of the present invention;

FIG. 6B is a diagrammatic illustration of an applicator in accordancewith another embodiment of the present invention;

FIG. 7 is a flow chart illustrating a variation of the method of FIG. 4using a cap stylet in accordance with one embodiment of the presentinvention;

FIG. 8 is a diagrammatic illustration of a cap stylet in accordance withone embodiment of the present invention;

FIG. 9 is a flow chart illustrating a method of applying a coating to acatheter using an applicator and cap stylet in accordance with oneembodiment of the present invention;

FIG. 10 is a diagrammatic illustration of the interaction of a catheter,applicator, and cap stylet in accordance with one embodiment of thepresent invention;

FIG. 11 is a flow chart illustrating a variation of the method of FIG.4, in accordance with one embodiment of the present invention;

FIG. 12 is a flow chart illustrating another variation of the method ofFIG. 4, in accordance with one embodiment of the present invention;

FIG. 13 is a flow chart illustrating another variation of the method ofFIG. 4, in accordance with one embodiment of the present invention; and

FIG. 14 is a diagrammatic illustration of a coated medical device inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION

An illustrative embodiment of the present invention relates to theprovision of a coating on an implantable medical device. The coating caninclude a bio-absorbable carrier component. In addition to thebio-absorbable carrier component, a therapeutic agent component can alsobe provided. However, the coating is not limited to a bio-absorbablecarrier component or a therapeutic agent component. Rather, anyvariation of coating formed with application of a relatively liquid orfluent material that is desired for application to a medical device canbe applied using the applicator and method of the present invention. Thecoated medical device can be implantable in a patient to affectcontrolled delivery of the coating to the patient, or can be forexternal use.

As utilized herein, the term “bio-absorbable” generally refers to havingthe property or characteristic of being able to penetrate the tissue ofa patient's body. In certain embodiments of the present inventionbio-absorption occurs through a lipophilic mechanism. The bio-absorbablesubstance is soluble in the phospholipid bi-layer of cells of bodytissue, and therefore impacts how the bio-absorbable substancepenetrates into the cells.

It should be noted that a bio-absorbable substance is different from abiodegradable substance. Biodegradable is generally defined as capableof being decomposed by biological agents, or capable of being brokendown by microorganisms or biological processes, in a manner that doesnot result in cellular uptake of the biodegradable substance.Biodegradation thus relates to the breaking down and distributing of asubstance through the patient's body, verses the penetration of thecells of the patient's body tissue. Biodegradable substances can causeinflammatory response due to either the parent substance or those formedduring breakdown, and they may or may not be absorbed by tissues.

The phrase “controlled release” generally refers to the release of abiologically active agent in a predictable manner over the time periodof weeks or months, as desired and predetermined upon formation of thebiologically active agent on the medical device from which it is beingreleased. Controlled release includes the provision of an initial burstof release upon implantation, followed by the predictable release overthe aforementioned time period.

With regard to the aforementioned oils, it is generally known that thegreater the degree of unsaturation in the fatty acids the lower themelting point of a fat, and the longer the hydrocarbon chain the higherthe melting point of the fat. A polyunsaturated fat, thus, has a lowermelting point, and a saturated fat has a higher melting point. Thosefats having a lower melting point are more often oils at roomtemperature. Those fats having a higher melting point are more oftenwaxes or solids at room temperature. Therefore, a fat having thephysical state of a liquid at room temperature is an oil. In general,polyunsaturated fats are liquid oils at room temperature, and saturatedfats are waxes or solids at room temperature.

Polyunsaturated fats are one of four basic types of fat derived by thebody from food. The other fats include saturated fat, as well asmonounsaturated fat and cholesterol. Polyunsaturated fats can be furthercomposed of omega-3 fatty acids and omega-6 fatty acids. Under theconvention of naming the unsaturated fatty acid according to theposition of its first double bond of carbons, those fatty acids havingtheir first double bond at the third carbon atom from the methyl end ofthe molecule are referred to as omega-3 fatty acids. Likewise, a firstdouble bond at the sixth carbon atom is called an omega-6 fatty acid.There can be both monounsaturated and polyunsaturated omega fatty acids.

Omega-3 and omega-6 fatty acids are also known as essential fatty acidsbecause they are important for maintaining good health, despite the factthat the human body cannot make them on its own. As such, omega-3 andomega-6 fatty acids must be obtained from external sources, such asfood. Omega-3 fatty acids can be further characterized as containingeicosapentaenoic acid (EPA), docosahexanoic acid (DHA), andalpha-linolenic acid (ALA). Both EPA and DHA are known to haveanti-inflammatory effects and wound healing effects within the humanbody.

Oil that is hydrogenated becomes a waxy solid. Attempts have been madeto convert the polyunsaturated oils into a wax or solid to allow the oilto adhere to a device for a longer period of time. One such approach isknown as hydrogenation, which is a chemical reaction that adds hydrogenatoms to an unsaturated fat (oil) thus saturating it and making it solidat room temperature. This reaction requires a catalyst, such as a heavymetal, and high pressure. The resultant material forms a non-crosslinkedsemi-solid. Hydrogenation can reduce or eliminate omega-3 fatty acids,and any therapeutic effects (both anti-inflammatory and wound healing)they offer.

In addition, some curing methods have been indicated to have detrimentaleffects on the therapeutic agent combined with the omega-3 fatty acid,making them partially or completely ineffective. As such, oils, and morespecifically oils containing omega-3 fatty acids, have been utilized asa delivery agent for the short term uncontrolled release of atherapeutic agent, so that minimal or no curing is required. However,there are no known uses of oils containing omega-3 fatty acids forcombination with a therapeutic agent in a controlled release applicationthat makes use of the therapeutic benefits of the omega-3 fatty acids.Further, some heating of the omega-3 fatty acids to cure the oil canlessen the total therapeutic effectiveness of the omega-3 fatty acids,but not eliminate the therapeutic effectiveness. One characteristic thatcan remain after certain curing by heating methods is thenon-inflammatory response of the tissue when exposed to the curedmaterial. As such, an oil containing omega-3 fatty acids can be heatedfor curing purposes, and still maintain some or even a substantialportion of the therapeutic effectiveness of the omega-3 fatty acids. Inaddition, although the therapeutic agent combined with the omega-3 fattyacid and cured with the omega-3 fatty acid can be rendered partiallyineffective, the portion remaining of the therapeutic agent can, inaccordance with the present invention, maintain pharmacological activityand in some cases be more effective than an equivalent quantity of agentdelivered with other coating delivery agents. Thus, if for example, 80%of a therapeutic agent is rendered ineffective during curing, theremaining 20% of therapeutic agent, combined with and delivered by thecoating can be efficacious in treating a medical disorder, and in somecases have a relatively greater therapeutic effect than the samequantity of agent delivered with a polymeric or other type of coating.

For long term controlled release applications, polymers, as previouslymentioned, have been utilized in combination with a therapeutic agent.Such a combination provides a platform for the controlled long termrelease of the therapeutic agent from a medical device. However,polymers have been determined to themselves cause inflammation in bodytissue. Therefore, the polymers often must include at least onetherapeutic agent that has an anti-inflammatory effect to counter theinflammation caused by the polymer delivery agent. In addition, patientsthat received a polymer-based implant must also follow a course of longterm systemic anti-platelet therapy to offset the thrombogenicproperties of the non-absorbable polymer. A significant percentage ofpatients that receive such implants are required to undergo additionalmedical procedures, such as surgeries (whether related follow-up surgeryor non-related surgery) and are required to stop their anti-platelettherapy. This can lead to a thrombotic event, such as stroke, which canlead to death. Use of the inventive coating described herein can negatethe necessity of anti-platelet therapy, and the corresponding relatedrisks described, because there is no thrombogenic polymer reaction tothe coating.

FIGS. 1 through 14, wherein like parts are designated by like referencenumerals throughout, illustrate example embodiments of an applicator andcorresponding method for coating a medical device, along withrepresentative coated medical device examples. Although the presentinvention will be described with reference to the example embodimentsillustrated in the figures, it should be understood that manyalternative forms can embody the present invention. One of ordinaryskill in the art will additionally appreciate different ways to alterthe parameters of the embodiments disclosed, such as the size, shape, ortype of elements or materials, in a manner still in keeping with thespirit and scope of the present invention.

FIG. 1 illustrates a stent 10 in accordance with one embodiment of thepresent invention. The stent 10 is representative of a medical devicethat is suitable for having a coating applied thereon to affect atherapeutic result. The stent 10 is formed of a series of interconnectedstruts 12 having gaps 14 formed therebetween. The stent 10 is generallycylindrically shaped. Accordingly, the stent 10 maintains an interiorsurface 16 and an exterior surface 18.

One of ordinary skill in the art will appreciate that the illustrativestent 10 is merely exemplary of a number of different types of stentsavailable in the industry. For example, the strut 12 structure can varysubstantially. The material of the stent can also vary from a metal,such as stainless steel, Nitinol, nickel, tantalum, magnesium, andtitanium alloys, to cobalt chromium alloy, ceramic, plastic, and polymertype materials. One of ordinary skill in the art will further appreciatethat the present invention is not limited to use on stents. Instead, thepresent invention has application on a wide variety of medical devices.For purposes of clarity, the following description will refer to a stentas the exemplar medical device. The terms medical device and stent areinterchangeable with regard to the applicability of the presentinvention. Accordingly, reference to one or another of the stent, or themedical device, is not intended to unduly limit the invention to thespecific embodiment described.

FIG. 2 illustrates one example embodiment of the stent 10 having acoating 20 applied thereon in accordance with the present invention.FIG. 3 is likewise an alternative embodiment of the stent 10 having thecoating 20 also applied thereon. The coating 20 is applied to themedical device, such as the stent 10, to provide the stent 10 withdifferent surface properties, and also to provide a vehicle fortherapeutic applications.

In FIG. 2, the coating 20 is applied on both the interior surface 16 andthe exterior surface 18 of the strut 12 forming the stent 10. In otherwords, the coating 20 in FIG. 2 substantially encapsulates the struts 12of the stent 10. In FIG. 3, the coating 20 is applied only on theexterior surface 18 of the stent 10, and not on the interior surface 16of the stent 10. The coating 20 in both configurations is the samecoating; the difference is merely the portion of the stent 10 that iscovered by the coating 20. One of ordinary skill in the art willappreciate that the coating 20 as described throughout the Descriptioncan be applied in both manners shown in FIG. 2 and FIG. 3, in additionto other configurations such as, partially covering select portions ofthe stent 10 structure. All such configurations are described by thecoating 20 reference.

In some instances of the resulting coated medical device, the stent 10includes the coating 20, which is bio-absorbable. The coating 20 has abio-absorbable carrier component, and can also include a therapeuticagent component that can also be bio-absorbable. When applied to amedical device such as a stent 10, it is often desirable for the coatingto inhibit or prevent restenosis. Restenosis is a condition whereby theblood vessel experiences undesirable cellular remodeling after injury.When a stent is implanted in a blood vessel, and expanded, the stentitself may cause some injury to the blood vessel. The treated vesseltypically has a lesion present which can contribute to the inflammationand extent of cellular remodeling. The end result is that the tissue hasan inflammatory response to the conditions. Thus, when a stent isimplanted, there is often a need for the stent to include a coating thatinhibits inflammation, or is non-inflammatory, and prevents restenosis.These coatings have been provided using a number of different approachesas previously described in the Background. However, none of the priorcoatings have utilized a bio-absorbable carrier component to create abio-absorbable coating with suitable non-inflammatory properties forcontrolled release of a therapeutic agent.

In some instances of the resultant coated medical device, thebio-absorbable carrier component is in the form of a naturally occurringoil. An example of a naturally occurring oil is fish oil or cod liveroil. A characteristic of the naturally occurring oil is that the oilincludes lipids, which contributes to the lipophilic action that ishelpful in the delivery of therapeutic agents to the cells of the bodytissue. In addition, the naturally occurring oil includes omega-3 fattyacids in accordance with several embodiments of the present invention.As previously described, omega-3 fatty acids and omega-6 fatty acids areknown as essential fatty acids. Omega-3 fatty acids can be furthercharacterized as eicosapentaenoic acid (EPA), docosahexanoic acid (DHA),and alpha-linolenic acid (ALA). Both EPA and DHA are known to haveanti-inflammatory effects and wound healing effects within the humanbody.

In further detail, the term “bio-absorbable” generally refers to havingthe property or characteristic of being able to penetrate the tissues ofa patient's body. The bio-absorbable coating contains lipids, many ofwhich originate as triglycerides. It has previously been demonstratedthat triglyceride products such as partially hydrolyzed triglyceridesand fatty acid molecules can integrate into cellular membranes andenhance the solubility of drugs into the cell. Whole triglycerides areknown not to enhance cellular uptake as well as partially hydrolyzedtriglyceride, because it is difficult for whole triglycerides to crosscell membranes due to their relatively larger molecular size. Vitamin Ecompound can also integrate into cellular membranes resulting indecreased membrane fluidity and cellular uptake.

It is also known that damaged vessels undergo oxidative stress. Acoating containing an antioxidant such as alpha-tocopherol may aid inpreventing further damage by this mechanism.

Compounds that move too rapidly through a tissue may not be effective inproviding a sufficiently concentrated dose in a region of interest.Conversely, compounds that do not migrate in a tissue may never reachthe region of interest. Cellular uptake enhancers such as fatty acidsand cellular uptake inhibitors such as alpha-tocopherol can be usedalone or in combination to provide an effective transport of a givencompound to a given region or location. Both fatty acids andalpha-tocopherol are accommodated by the coating of the presentinvention described herein. Accordingly, fatty acids andalpha-tocopherol can be combined in differing amounts and ratios tocontribute to a coating in a manner that provides control over thecellular uptake characteristics of the coating and any therapeuticagents mixed therein.

It should further be emphasized that the bio-absorbable nature of thecarrier component and the resulting coating (in the instances where abio-absorbable therapeutic agent component is utilized) results in thecoating 20 being completely absorbed over time by the cells of the bodytissue. There are no break down products of the coating that induce aninflammatory response. In short, the coating 20 is generally composed offatty acids, including in some instances omega-3 fatty acids, bound totriglycerides, potentially also including a mixture of free fatty acidsand vitamin E. The triglycerides are broken down by lipases (enzymes)which result in free fatty acids that can than be transported acrosscell membranes. Subsequently, fatty acid metabolism by the cell occursto metabolize any substances originating with the coating. Thebio-absorbable nature of the coating thus results in the coating beingabsorbed, leaving only an underlying delivery or other medical devicestructure. There is no foreign body response to the bio-absorbablecarrier component, including no inflammatory response. The modificationof the oils from a more liquid physical state to a more solid, but stillflexible, physical state is implemented through the curing process. Asthe oils are cured, especially in the case of fatty acid-based oils suchas fish oil, cross-links form creating a gel. As the curing process isperformed over increasing time durations and/or increasing temperatureconditions, more cross-links form transitioning the gel from arelatively liquid gel to a relatively solid-like, but still flexible,gel structure.

The coating can also include a therapeutic agent component. Thetherapeutic agent component mixes with the bio-absorbable carriercomponent as described later herein. The therapeutic agent component cantake a number of different forms including but not limited toanti-oxidants, anti-inflammatory agents, anti-coagulant agents, drugs toalter lipid metabolism, anti-proliferatives, anti-neoplastics, tissuegrowth stimulants, functional protein/factor delivery agents,anti-infective agents, anti-imaging agents, anesthetic agents,therapeutic agents, tissue absorption enhancers, anti-adhesion agents,germicides, antiseptics, proteoglycans, GAG's, gene delivery(polynucleotides), polysaccharides (e.g., heparin), anti-migratoryagents, pro-healing agents, ECM/protein production inhibitors,analgesics, prodrugs, and any additional desired therapeutic agents suchas those listed in Table 1 below.

TABLE #1 CLASS EXAMPLES Antioxidants Alpha-tocopherol, lazaroid,probucol, phenolic antioxidant, resveretrol, AGI-1067, vitamin EAntihypertensive Agents Diltiazem, nifedipine, verapamilAntiinflammatory Agents Glucocorticoids (e.g. dexamethazone,methylprednisolone), leflunomide, NSAIDS, ibuprofen, acetaminophen,hydrocortizone acetate, hydrocortizone sodium phosphate,macrophage-targeted bisphosphonates Growth Factor Angiopeptin, trapidil,suramin Antagonists Antiplatelet Agents Aspirin, dipyridamole,ticlopidine, clopidogrel, GP IIb/IIIa inhibitors, abcximab AnticoagulantAgents Bivalirudin, heparin (low molecular weight and unfractionated),wafarin, hirudin, enoxaparin, citrate Thrombolytic Agents Alteplase,reteplase, streptase, urokinase, TPA, citrate Drugs to Alter LipidFluvastatin, colestipol, lovastatin, atorvastatin, amlopidine Metabolism(e.g. statins) ACE Inhibitors Elanapril, fosinopril, cilazaprilAntihypertensive Agents Prazosin, doxazosin Antiproliferatives andCyclosporine, cochicine, mitomycin C, sirolimus Antineoplasticsmicophenonolic acid, rapamycin, everolimus, tacrolimus, paclitaxel,QP-2, actinomycin, estradiols, dexamethasone, methatrexate, cilostazol,prednisone, cyclosporine, doxorubicin, ranpirnas, troglitzon, valsarten,pemirolast, C- MYC antisense, angiopeptin, vincristine, PCNA ribozyme,2-chloro-deoxyadenosine Tissue growth stimulants Bone morphogeneicprotein, fibroblast growth factor Promotion of hollow Alcohol, surgicalsealant polymers, polyvinyl particles, 2- organ occlusion or octylcyanoacrylate, hydrogels, collagen, liposomes thrombosis FunctionalProtein/Factor Insulin, human growth hormone, estradiols, nitric oxide,delivery endothelial progenitor cell antibodies Second messenger Proteinkinase inhibitors targeting Angiogenic Angiopoetin, VEGF Anti-AngiogenicEndostatin Inhibitation of Protein Halofuginone, prolyl hydroxylaseinhibitors, C-proteinase Synthesis/ECM formation inhibitorsAntiinfective Agents Penicillin, gentamycin, adriamycin, cefazolin,amikacin, ceftazidime, tobramycin, levofloxacin, silver, copper,hydroxyapatite, vancomycin, ciprofloxacin, rifampin, mupirocin, RIP,kanamycin, brominated furonone, algae byproducts, bacitracin, oxacillin,nafcillin, floxacillin, clindamycin, cephradin, neomycin, methicillin,oxytetracycline hydrochloride, Selenium. Gene Delivery Genes for nitricoxide synthase, human growth hormone, antisense oligonucleotides LocalTissue perfusion Alcohol, H2O, saline, fish oils, vegetable oils,liposomes Nitric oxide Donor NCX 4016 - nitric oxide donor derivative ofaspirin, Derivatives SNAP Gases Nitric oxide, compound solutions ImagingAgents Halogenated xanthenes, diatrizoate meglumine, diatrizoate sodiumAnesthetic Agents Lidocaine, benzocaine Descaling Agents Nitric acid,acetic acid, hypochlorite Anti-Fibrotic Agents Interferon gamma-1b,Interluekin-10 Immunosuppressive/Immunomodulatory Cyclosporine,rapamycin, mycophenolate motefil, Agents leflunomide, tacrolimus,tranilast, interferon gamma-1b, mizoribine Chemotherapeutic AgentsDoxorubicin, paclitaxel, tacrolimus, sirolimus, fludarabine, ranpirnaseTissue Absorption Fish oil, squid oil, omega 3 fatty acids, vegetableoils, Enhancers lipophilic and hydrophilic solutions suitable forenhancing medication tissue absorption, distribution and permeationAnti-Adhesion Agents Hyaluronic acid, human plasma derived surgicalsealants, and agents comprised of hyaluronate and carboxymethylcellulosethat are combined with dimethylaminopropyl, ehtylcarbodimide,hydrochloride, PLA, PLGA Ribonucleases Ranpirnase Germicides Betadine,iodine, sliver nitrate, furan derivatives, nitrofurazone, benzalkoniumchloride, benzoic acid, salicylic acid, hypochlorites, peroxides,thiosulfates, salicylanilide Antiseptics Selenium AnalgesicsBupivicaine, naproxen, ibuprofen, acetylsalicylic acid

Some specific examples of therapeutic agents useful in theanti-restenosis realm include cerivastatin, cilostazol, fluvastatin,lovastatin, paclitaxel, pravastatin, rapamycin, a rapamycin carbohydratederivative (for example as described in US Patent ApplicationPublication 2004/0235762), a rapamycin derivative (for example asdescribed in U.S. Pat. No. 6,200,985), everolimus, seco-rapamycin,seco-everolimus, and simvastatin. Depending on the type of therapeuticagent component added to the coating, the resulting coating can bebio-absorbable if the therapeutic agent component is alsobio-absorbable. As described in the Summary of the Invention, thepresent invention relates to coating a medical device with a coating.The coating is formed of at least two primary components, namely abio-absorbable carrier component and a therapeutic agent component. Thetherapeutic agent component has some form of therapeutic or biologicaleffect. The bio-absorbable carrier component can also have a therapeuticor biological effect. It should again be noted that the bio-absorbablecarrier component is different from the conventional bio-degradablesubstances utilized for similar purposes. The bio-absorbablecharacteristic of the carrier component enables the cells of body tissueof a patient to absorb the bio-absorbable carrier component itself,rather than breaking down the carrier component into inflammatoryby-products and disbursing said by-products of the component forultimate elimination by the patient's body. Accordingly,anti-inflammatory drug dosages to the patient do not need to beincreased to additionally compensate for inflammation caused by thecarrier component, as is otherwise required when using polymer-basedcarriers that themselves cause inflammation.

It should also be noted that the present description makes use of thestent 10 as an example of a medical device that can be coated with thecoating 20 of the present invention. However, the present invention isnot limited to use with the stent 10. Instead, any number of otherimplantable medical devices can be coated in accordance with theteachings of the present invention with the described coating 20. Suchmedical devices include catheters, grafts, balloons, prostheses, stents,other medical device implants, and the like. Implantation refers to bothtemporarily implantable medical devices, as well as permanentlyimplantable medical devices. In the instance of the example stent 10, acommon requirement of stents is that they include some substance oragent that inhibits restenosis. Accordingly, the example coating 20 asdescribed is directed toward the reduction or the elimination ofrestenosis. However, one of ordinary skill in the art will appreciatethat the coating 20 can have other therapeutic or biological benefits.The composition of the coating 20 is simply modified or mixed in adifferent manner to result in a different biological effect.

FIG. 4 illustrates one method of making a coated medical device, in theform of the coated stent 10. The process involves providing a medicaldevice, such as the stent 10 (step 100). A coating, such as coating 20,is then applied to the medical device (step 102). One of ordinary skillin the art will appreciate that this basic method of application of acoating to a medical device such as the stent 10 can have a number ofdifferent variations falling within the process described. Depending onthe particular application, the stent 10 with the coating 20 appliedthereon can be implanted after the coating 20 is applied, or additionalsteps such as curing, sterilization, and removal of solvent can beapplied to further prepare the stent 10 and coating 20. Furthermore, ifthe coating 20 includes a therapeutic agent that requires some form ofactivation (such as UV light), such actions can be implementedaccordingly.

In one embodiment of the present invention, applying the coating to themedical device involves using an applicator to apply the coating. Theuse of an applicator allows for application of coating having improveduniformity and coverage. An exemplary method of this can be seen in FIG.5. The method involves providing a medical device onto which a coatingis to be applied (step 202); providing a coating substance forapplication onto the medical device (step 204); and applying the coatingsubstance to the medical device using an applicator (step 206). Incertain embodiments, the method may further include the step of curingthe coating substance to form a coating on the medical device (step208).

An exemplary embodiment of an applicator 300 can be seen in FIG. 6A. Theapplicator 300 is formed of a sheath 302 having a first end 304, asecond end 306 and a lumen 308 between the first 304 and second 306ends. The first end 304 is flared and has a cross-sectional area greaterthan a cross sectional area of a portion of the lumen 308. The sheath302 is sized and dimensioned to fit over the medical device 310, whileproviding a clearance between the sheath 302 and the medical device 310for receiving a coating substance for application to the medical device310. In some embodiments, the second end 306 may also be flared and havea cross-sectional area greater than a cross-sectional area of at least aportion of the lumen 308, as can be seen in FIG. 6B. Examples of medicaldevices 310 on which the applicator 300 may be used include stents andcatheters. In certain embodiments, a coating is applied to a stent thathas been positioned on the end of a catheter. Preferably, the applicator300 is formed of plastic but other suitable material that can be formedinto the desired configuration can be used.

In the present embodiment the cross-section shape of the applicator iscircular giving the applicator a funnel or trumpet like shape. Othersuitable cross sectional shapes include polygonal shapes such ashexagonal, octagonal, or the like. Other possible shapes andconfigurations will be apparent to one skilled in the art given thebenefit of this disclosure.

In use, the coating is applied by placing the applicator 300 onto themedical device 310 and then filling the applicator 300 with the coatingsubstance. The flared nature of the first end 304 assists in providing alarger opening for receiving the coating substance and directing it ontothe medical device. The coating substance may be placed into theapplicator 300, for example, at flared first end 304, or be placed ontothe medical device 310 directly. In certain embodiments the coatingsubstance is delivered using metering device, such as a syringe, so thatthe amount of coating, and in certain cases, dosage of therapeuticagent, can be controlled.

In the present embodiment the applicator 300 is configured to slide ontothe medical device 310. In other embodiments, the applicator 300 may beformed of two halves that are joined together around the medical device310. Other possible configurations will be apparent to one skilled giventhe benefit of this disclosure.

In certain embodiments, after the applicator 300 has been filled withcoating substance, the applicator 300 can be removed. In the presentembodiment, wherein the applicator 300 is configured to slide onto themedical device 310, removing the applicator 300 is performed by slidingthe applicator 300 off the medical device 310. Alternately, the coatingsubstance may be applied directly to the medical device 310 and theapplicator 300 is then slid over the medical device 310 to spread thecoating substance over the medical device 310. In this embodiment, theclearance between the sheath 302 and the medical device 310 isdimensioned and sized to leave a residual coating of the coatingsubstance on the medical device 310 as the applicator 300 is slid overthe medical device 310. Preferably, the clearance is between 0.0001 to0.1 inches. More preferably, the clearance is between 0.001 to 0.01inches. In certain embodiments the uniformity and coverage of such aresidual coating can be improved by sliding the applicator 300 over themedical device 310 with a twisting motion.

In certain embodiments, as set forth in step 208 of FIG. 5, once thecoating substance has been applied to the medical device, the coatingsubstance is cured to form the coating on the medical device. Curing canbe performed after the applicator has been removed, or with theapplicator still in place over the medical device. Curing with respectto the present invention generally refers to thickening, hardening, ordrying of a material brought about by heat, UV, reactive gases, orchemical means.

In some embodiments, once the coating has been formed on the medicaldevice 310, a protective sleeve 314 is placed over the medical device310 to protect the coating on the medical device 310 during furtherhandling. In an exemplary embodiment, the protective sleeve 314 isformed of plastic, and sized and dimensioned to fit over the medicaldevice 310. Other suitable implementations will be apparent to oneskilled in the art given the benefit of this disclosure.

In certain embodiments wherein a coating is being applied to a catheter,a cap, such as cap stylet, may be used when applying the coatingsubstance. When placed on the end of a catheter, the cap preventscoating substance from penetrating the lumen at the end of the catheter.An exemplary embodiment of such a method can be seen in FIG. 7. In thisembodiment, the method involves providing a catheter onto which acoating is to be applied (step 402), providing a coating substance forapplication onto the catheter (step 404), providing a cap configured tofit onto an end of the catheter (step 406); placing the cap onto an endof the catheter (step 408), and applying the coating substance onto thecatheter (step 410).

The cap comprises a section of tubing configured to fit on the end ofthe catheter to seal the lumen at the end of the catheter during theapplication of a coating. An exemplary embodiment of a cap and itsinteraction with a catheter can be seen in FIG. 8. In this embodimentthe cap is a cap stylet 500. The catheter 520 has a proximal end (notshown), a distal end 522, and a lumen 524 between the proximal anddistal ends. The cap stylet 500 features a stylet 502 configured to fillthe lumen 524 of the catheter 520; and a section of tubing 504 attachedto the stylet 502 sized and dimensioned to be fitted on the end of thecatheter 520 to seal the lumen 524 of the catheter 520. In certainembodiments, the section of tubing 504 is sized to pinch fit on the endof a catheter 520. Alternately, the cap can snap or interference fit onthe end of the catheter. When placed on the end of a catheter 520, thecap stylet 500 prevents the coating substance from wicking into thelumen 524 at the end of the catheter 520 as a coating is applied. If thecoating substance gets into the lumen 524 it could create an obstructionthat may adversely effect the operation of the catheter 520. Preferably,the cap stylet 500 is placed on the distal end 522 of the catheter 520,which is to be inserted into a patient, and is thus coated. In certainembodiments wherein the whole catheter is to be coated, a cap stylet 500can be placed on each end of the catheter 520.

Once the cap, in this case a cap stylet 500, has been placed on the endof the catheter 520, the coating can then be applied to the catheter(step 410 of FIG. 7). In certain embodiments this involves using anapplicator as set forth above. The coating may also be applied by dipcoating, spray coating, printing, wiping, electrostatic coating,brushing, painting or any means suitable for applying the coatingsubstance.

Once the coating substance has been applied, the coating substance canthen be cured as discussed above. Likewise, in some embodiments aprotective sleeve 510 may be placed on the catheter 520 to protect thecoating.

Another exemplary embodiment of a method, wherein an applicator and acap stylet are used in forming a coating on a catheter, can bee seen inFIG. 9. In this embodiment, the method includes providing a catheter(step 600), providing the coating substance for application onto thecatheter (step 602), providing a cap stylet configured to fit onto anend of the catheter (step 604), providing an applicator configured toapply a coating to the catheter (step 606), placing the cap stylet ontoan end of the catheter (step 608) and applying the coating substanceonto the catheter using the applicator (step 610).

The methodology of FIG. 9 may be better understood if viewed inconjunction with the exemplary embodiment of FIG. 10 of a system 700 forapplying a coating to a medical device. In this instance, a catheter 720has a stent 710 pre-positioned on the distal end 722 of the catheterimplantation in a patient. A cap stylet 730 is placed unto the distalend 722 of the catheter 720. The cap stylet 730 features a stylet 732configured to fill a lumen 724 of the catheter 720, and a section oftubing 734 attached to the stylet 732 sized and dimensioned to be fittedon an end of the catheter 720 to seal the lumen 724 of the catheter 720.An applicator 740 is then slid onto the catheter 720 beyond the stent710. The applicator 740 features a sheath 742 having a first end 744, asecond end 746 and a lumen 748 between the first 744 and second 746ends. The first end 744 is flared and has a cross-sectional area greaterthan a cross-sectional area of at least a portion of the lumen 748. Thesheath 742 is sized and dimensioned to fit over the catheter 720,providing a clearance between the sheath 742 and the catheter 720 forreceiving a coating substance for application to the catheter. Thecoating substance is then applied. In this embodiment, the applicator740 is filled with coating substance at the flared first end 744 using ametering device, such as a syringe, to ensure the proper amount ofcoating substance is applied. Alternately, the coating substance may beapplied directly to the catheter 720. The applicator 740 is then slidoff the catheter 720 over the stent 710 and cap stylet 730 in thedirection of arrow 760 using a twisting motion. The clearance betweenthe sheath 742 and the catheter 720 is sized and dimensioned to leave aresidual coating of the coating substance as the applicator 740 is slidover the catheter 720.

In certain embodiments, once the coating substance 750 has been applied,the coating substance 750 may be cured as discussed above. Likewise, aprotective sleeve can be placed over the catheter 720 and stent 710 toprotect the coating during further handling.

FIG. 11 is a flowchart illustrating another example implementation ofthe method of FIG. 4. In accordance with the steps illustrated in FIG.11, a bio-absorbable carrier component is provided along with atherapeutic agent component (step 810). The provision of thebio-absorbable carrier component and the provision of the therapeuticagent component can occur individually, or in combination, and can occurin any order or simultaneously. The bio-absorbable carrier component ismixed with the therapeutic agent component (or vice versa) to form acoating substance (step 820). The coating substance is applied to themedical device, such as a stent or catheter, to form the coating (step830). The coated medical device is then sterilized using any number ofdifferent sterilization processes (step 840). For example, sterilizationcan be implemented utilizing ethylene oxide, gamma radiation, E beam,steam, gas plasma, or vaporized hydrogen peroxide. One of ordinary skillin the art will appreciate that other sterilization processes can alsobe applied, and that those listed herein are merely examples ofsterilization processes that result in a sterilization of the coatedstent, preferably without having a detrimental effect on the coating 20.

The formation of the bio-absorbable carrier component and thetherapeutic agent component can be done in accordance with differentmethods. FIG. 12 is a flow chart illustrating one example method forforming each of the components. Vitamin E is mixed with a bio-absorbablecarrier to form a bio-absorbable carrier component (step 910). A solventis mixed with a therapeutic agent to form a therapeutic agent component(step 920). The solvent can be chosen from a number of differentalternatives, including ethanol or N-Methyl-2-Pyrrolidone (NMP). Thebio-absorbable carrier component is then mixed with the therapeuticagent component to form the coating substance (step 930). The solventcan then be removed with vacuum or heat. It should be noted that thepreparation of the bio-absorbable carrier component and the therapeuticagent component can be done in either order, or substantiallysimultaneously. Additionally, in an alternative approach, the solventcan be omitted altogether.

In accordance with another technique, a surface preparation orpre-treatment 22, as shown in FIG. 14, is provided on a stent 10. Morespecifically and in reference to the flowchart of FIG. 13, apre-treatment substance or base coating is first provided (step 1010).The pre-treatment substance or base coating is applied to a medicaldevice, such as the stent 10, to prepare the medical device surface forapplication of the coating (step 1020). If desired, the pre-treatment orbase coating 22 is cured (step 1030). Curing methods can includeprocesses such as application of UV light, heat, reactive gases, orchemical means to cure the pre-treatment 22. A coating substance is thenapplied on top of the pre-treatment 22 (step 1040). The coated medicaldevice is then sterilized using any number of sterilization processes aspreviously mentioned (step 1050).

FIG. 14 illustrates the stent 10 having two coatings, specifically, thepre-treatment 22 and the coating 20. The pre-treatment 22 serves as abase or primer for the coating 20. The coating 20 conforms and adheresbetter to the pre-treatment 22 verses directly to the stent 10,especially if the coating 20 is not heat or UV cured. The pre-treatmentcan be formed of a number of different materials or substances. Inaccordance with one example embodiment of the present invention, thepre-treatment is formed of a bio-absorbable substance, such as anaturally occurring oil (e.g., fish oil). The bio-absorbable nature ofthe pre-treatment 22 results in the pre-treatment 22 ultimately beingabsorbed by the cells of the body tissue after the coating 20 has beenabsorbed.

It has been previously mentioned that curing of substances such as fishoil can reduce or eliminate some of the therapeutic benefits of theomega-3 fatty acids, including anti-inflammatory properties and healingproperties. However, if the coating 20 contains the bio-absorbablecarrier component formed of the oil having the therapeutic benefits, thepre-treatment 22 can be cured to better adhere the pre-treatment 22 tothe stent 10, without losing all of the therapeutic benefits resident inthe pre-treatment 22, or in the subsequently applied coating 20.Furthermore, the cured pre-treatment 22 provides better adhesion for thecoating 20 relative to when the coating 20 is applied directly to thestent 10 surface. In addition, the pre-treatment 22, despite beingcured, remains bio-absorbable, like the coating 20.

The pre-treatment 22 can be applied to both the interior surface 16 andthe exterior surface 18 of the stent 10, if desired, or to one or theother of the interior surface 16 and the exterior surface 18.Furthermore, the pre-treatment 22 can be applied to only portions of thesurfaces 16 and 18, or to the entire surface, if desired.

The application of the coating to the medical device can take place in amanufacturing-type facility and subsequently shipped and/or stored forlater use. Alternatively, the coating can be applied to the medicaldevice just prior to implantation in the patient. The process utilizedto prepare the medical device will vary according to the particularembodiment desired. In the case of the coating being applied in amanufacturing-type facility, the medical device is provided with thecoating and subsequently sterilized in accordance with any of themethods provided herein, and/or any equivalents. The medical device isthen packaged in a sterile environment and shipped or stored for lateruse. When use of the medical device is desired, the medical device isremoved from the packaging and implanted in accordance with its specificdesign.

In the instance of the coating being applied just prior to implantation,the medical device can be prepared in advance. The medical device, forexample, can be sterilized and packaged in a sterile environment forlater use. When use of the medical device is desired, the medical deviceis removed from the packaging, and the coating substance is applied toresult in the coating resident on the medical device.

The present invention provides methods and devices for applying acoating to medical devices such as a stent. The methods and devices ofthe present invention provide a means for applying a coating thatprovides improved uniformity and coverage in a repeatable and controlledmanner. The methods and devices also provide increased consistency incoating from device to device. This in turn allows for greater controlof dosage of the bio-absorbable carrier and therapeutic agent.

Numerous modifications and alternative embodiments of the presentinvention will be apparent to those skilled in the art in view of theforegoing description. Accordingly, this description is to be construedas illustrative only and is for the purpose of teaching those skilled inthe art the best mode for carrying out the present invention. Details ofthe structure may vary substantially without departing from the spiritof the invention, and exclusive use of all modifications that comewithin the scope of the appended claims is reserved. It is intended thatthe present invention be limited only to the extent required by theappended claims and the applicable rules of law.

1. A method of preparing a coated medical device, the method comprising:providing a medical device onto which a coating is to be applied;providing a coating substance for application onto the medical device;and applying the coating substance to the medical device using anapplicator comprising a sheath having a first end, a second end, and alumen between the first end and the second end, the first end beingflared and having a cross-sectional area greater than a cross-sectionalarea of at least a portion of the lumen; wherein the sheath is sized anddimensioned to fit over the medical device providing a clearance betweenthe sheath and the medical device for receiving the coating substancefor application to the medical device; and wherein the coating substancethat is received for application to the medical device is not thesheath.
 2. The method of claim 1 wherein applying the coating substanceto the medical device comprises: placing the applicator onto the medicaldevice; and filling the applicator with the coating substance.
 3. Themethod of claim 2, wherein placing the applicator onto the medicaldevice comprises sliding the applicator onto the medical device.
 4. Themethod of claim 2, further comprising removing the applicator from themedical device leaving a residual coating of the coating substance onthe medical device.
 5. The method of claim 4, wherein removing theapplicator from the medical device comprises sliding the applicator offof the medical device.
 6. The method of claim 5, wherein the applicatoris slid off the medical device with a twisting motion.
 7. The method ofclaim 2, wherein the applicator is filled using a metering device. 8.The method of claim 1, wherein applying the coating substance to themedical device comprises: placing the coating substance on the medicaldevice; and spreading the coating substance over the medical device bysliding the applicator over the medical device.
 9. The method of claim8, wherein the applicator is slid over the medical device using atwisting motion.
 10. The method of claim 8, wherein the coatingsubstance is placed on the medical device using a metering device. 11.The method of claim 1, further comprising the step of curing the coatingsubstance to form a coating on the medical device.
 12. The method ofclaim 1, further comprising sterilizing the coated medical device. 13.The method of claim 1, further comprising the step of placing aprotective sleeve over the medical device to protect the coating on themedical device.
 14. The method of claim 1, wherein the medical devicecomprises a stent.
 15. The method of claim 1, wherein the medical devicecomprises a catheter.
 16. The method of claim 1, wherein the medicaldevice comprises a balloon.
 17. The method of claim 1, wherein theclearance between the sheath and the medical device is sized anddimensioned to leave the coating substance on the medical device as thesheath is slid off over the medical device after the application of thecoating substance to the medical device.
 18. A method of applying acoating to a catheter, the method comprising: providing a catheterhaving a proximal end, a distal end, and a lumen between the proximaland distal ends; providing a coating substance for application onto thecatheter; providing a cap configured to fit onto an end of the catheter;placing the cap onto an end of the catheter; and applying the coatingsubstance onto the catheter; wherein, the cap prevents coating substancefrom penetrating the lumen at the end of the catheter.
 19. The method ofclaim 18, wherein the cap comprises a cap stylet comprising: a styletconfigured to fill a lumen of the catheter; and a section of tubingattached to the stylet sized and dimensioned to frictionally fit on anend of the catheter to seal the lumen of the catheter.
 20. The method ofclaim 19, wherein the cap stylet is placed on the distal end of thecatheter.
 21. The method of claim 18, wherein the provided catheter hasa stent on the distal end of the catheter.
 22. The method of claim 19,wherein the coating substance is applied to the end of the catheterwhere the cap stylet has been placed.
 23. The method of claim 18,wherein the coating is applied using a technique selected from the groupcomprising dip coating, spray coating, printing, wiping, electrostaticcoating, brushing, painting, and an applicator.
 24. The method of claim23, wherein the applicator comprises: a sheath having a first end, asecond end, and a lumen between the first end and the second end, thefirst end being flared and having a cross-sectional area greater than across-sectional area of at least a portion of the lumen; wherein thesheath is sized and dimensioned to fit over the catheter providing aclearance between the sheath and the catheter for receiving a coatingsubstance that is not the sheath for application to the catheter. 25.The method of claim 23, wherein applying the coating substance to themedical device comprises: placing the applicator onto the medicaldevice; and filling the applicator with the coating substance.
 26. Themethod of claim 25, wherein placing the applicator onto the medicaldevice comprises sliding the applicator onto the medical device.
 27. Themethod of claim 25, further comprising removing the applicator from themedical device leaving a residual coating of the coating substance onthe medical device.
 28. The method of claim 27, wherein removing theapplicator from the medical device comprises sliding the applicator offof the medical device.
 29. The method of claim 28, wherein theapplicator is slid off the medical device with a twisting motion. 30.The method of claim 25, wherein the applicator is filled using ametering device.
 31. The method of claim 23, wherein applying thecoating substance to the medical device comprises: placing the coatingsubstance on the medical device; and spreading the coating substanceover the medical device by sliding the applicator over the medicaldevice.
 32. The method of claim 31, wherein the applicator is slid overthe medical device using a twisting motion.
 33. The method of claim 31,wherein the coating substance is placed on the medical device using ametering device.
 34. The method of claim 18, further comprising the stepcuring the coating substance to form a coating on the medical device.35. The method of claim 18, further comprising sterilizing the coatedmedical device
 36. The method of claim 18, further comprising the stepof placing a protective sleeve over the medical device to protect thecoating on the medical device.
 37. The method of claim 24, wherein theclearance between the sheath and the medical device is sized anddimensioned to leave the coating substance on the medical device as thesheath is slid off over the medical device after the application of thecoating substance to the medical device.
 38. A method of coating acatheter, the method comprising: providing a catheter having a proximalend, a distal end, and a lumen between the proximal and distal ends;providing a coating substance for application onto the catheter;providing a cap stylet configured to fit onto an end of the catheter;providing an applicator comprising: a sheath having a first end and, asecond end, and a lumen between the first end and the second end, thefirst end being flared and having a cross-sectional area greater than across-sectional area of at least a portion of the lumen; wherein thesheath is sized and dimensioned to fit over the catheter providing aclearance between the sheath and the catheter for receiving a coatingsubstance for application to the catheter; placing the cap stylet ontoan end of the catheter; and applying the coating substance onto thecatheter using the applicator; wherein, the cap stylet prevents thecoating substance from penetrating the lumen at the end of the catheter;and wherein the coating substance applied is not the sheath.
 39. Themethod of claim 38, wherein the cap stylet comprises: a styletconfigured to fill a lumen of the catheter; and a section of tubingattached to the stylet sized and dimensioned to be fitted on an end ofthe catheter to seal the lumen of the catheter.
 40. The method of claim38, wherein the cap stylet is placed on the distal end of the catheter.41. The method of claim 40, wherein the provided catheter has a stent onthe distal end of the catheter.
 42. The method of claim 38, wherein thecoating substance is applied to the end of the catheter where the capstylet has been placed.
 43. The method of claim 38, wherein applying thecoating substance to the medical device comprises: placing theapplicator onto the medical device; and filling the applicator with thecoating substance.
 44. The method of claim 43, wherein placing theapplicator onto the medical device comprises sliding the applicator ontothe medical device.
 45. The method of claim 43, further comprisingremoving the applicator from the medical device leaving a residualcoating of the coating substance on the medical device.
 46. The methodof claim 45, wherein removing the applicator from the medical devicecomprises sliding the applicator off of the medical device.
 47. Themethod of claim 46, wherein the applicator is slid off the medicaldevice with a twisting motion.
 48. The method of claim 43, wherein theapplicator is filled using a metering device.
 49. The method of claim38, wherein applying the coating substance to the medical devicecomprises: placing the coating substance on the medical device; andspreading the coating substance over the medical device by sliding theapplicator over the medical device.
 50. The method of claim 49, whereinthe applicator is slid over the medical device using a twisting motion.51. The method of claim 49, wherein the coating substance is placed onthe medical device using a metering device.
 52. The method of claim 38,further comprising the step curing the coating substance to form acoating on the medical device.
 53. The method of claim 38, furthercomprising sterilizing the coated medical device.
 54. The method ofclaim 38, further comprising the steps of: providing a protective sleeveconfigured to fit onto the catheter; and placing the protective sleeveonto the catheter to protect the coating on the catheter.
 55. The methodof claim 38, wherein the clearance between the sheath and the medicaldevice is sized and dimensioned to leave the coating substance on themedical device as the sheath is slid off over the medical device afterthe application of the coating substance to the medical device.